High-resolution x-ray diffraction (HRXRD) and photoreflectance ( PR) spectroscopy were used to independently determine the In and N concentrations in GaInNAs alloys grown by solid-source molecular beam epitaxy (SSMBE). The lattice constant and bandgap energy can be expressed as two independent equations in terms of the In and N concentrations, respectively. The HRXRD measurement provided the lattice constant and the PR measurement extracted the bandgap energy. By simultaneously solving these two equations, we have determined the In and N concentrations with the error as small as 0.001.

The degradation of 1.3 mu m GaInNAs lasers was investigated using accelerated aging tests. This was followed by comprehensive characterization, including standard light-current-voltage (L-I-V) characterization, capacitance measurements, photoluminescence microscopy (PLM), on-axis amplified spontaneous emission (ASE) spectra measurements, and photocurrent (PC) and electroluminescence (EL) spectroscopies. The slope efficiency of the device dropped by 50% with a 300% increase in the threshold current after the accelerated aging test. The ideality factors of the aged devices are higher than those of the unaged devices. PLM images showed no evidence of catastrophic optical mirror damage. The measured capacitances of the aged devices are all similar to those of the unaged devices, indicating that there was no significant dopant diffusion in the junction region. Fourier transforms of the ASE spectra showed that no intracavity defects were present in the aged lasers, suggesting that intracavity defects are not responsible for the rapid degradation of the aged devices. Although the PC measurements showed defects at 0.88-0.95 eV and at similar to 0.76 eV, these defect signatures did not increase with aging. On the other hand, EL measurements revealed that radiative deep level defects were generated during the aging tests. which may be related to the degradation of the devices. Based on the above measurement results, we identify, the generation Of radiative deep level defects as the main causes of degradation of these devices.